1. Field of the Invention
The present disclosure relates to a reciprocating motor and a reciprocating compressor having a reciprocating motor.
2. Background of the Invention
Generally, a reciprocating compressor serves to intake, compress, and discharge a refrigerant as a piston linearly reciprocates within a cylinder. The reciprocating compressor may be classified into a connection type reciprocating compressor or a vibration type reciprocating compressor according to the method employed to drive the piston.
In the connection type reciprocating compressor, the piston is connected to a rotating shaft associated with a rotation motor by a connection rod, which causes the piston to reciprocate within the cylinder, thereby compressing the refrigerant. On the other hand, in the vibration type reciprocating compressor, the piston is connected to a mover associated with a reciprocating motor, which vibrates the piston while the piston reciprocates within the cylinder, thereby compressing the refrigerant. The present invention relates to the vibration type reciprocating compressor, and the term “reciprocating compressor” will hereinafter refer to the vibration type reciprocating compressor.
A conventional reciprocating compressor comprises a reciprocating motor including an outer stator and an inner stator, and a mover reciprocating between the inner stator and the outer stator. At least one air gap is provided between the inner stator and the outer stator to cause the mover to reciprocate.
In recent years, a so-called 1-air gap type reciprocating motor (hereinafter, referred to as “reciprocating motor”) having an air gap between the inner stator and the outer stator is known. FIGS. 1 to 4 are views showing a conventional 1-air gap type reciprocating motor.
As shown therein, the conventional reciprocating motor includes a stator 1 and a mover 5 reciprocally inserted into the stator 1.
The stator 1 includes an inner stator 2 and an outer stator 3 coupled to an outer circumferential surface of the inner stator 2.
The inner stator 2 is formed as a cylindrical shape by laminating a plurality of rectangular stator core sheets in a radial direction.
The outer stator 3 includes a plurality of stator blocks 3a formed by laminating a plurality of stator cores in a circular arc shape, the stator cores taking a cap-like shape to insert coils therein, and the plurality of stator blocks 3a being radially arranged in a circumferential direction on the outer circumferential surface of the inner stator 2.
A magnetic path connecting portion 1a is formed at a side of the stator 1 in a reciprocating direction to interconnect the outer circumferential surface of the inner stator 2 and an inner circumferential surface of the outer stator 3. An air gap portion 1b is formed on the opposite side of the magnetic path connecting portion 1a to insert the mover 5 therein.
The mover 5 includes a magnet holder 6 having a cylindrical shape and provided reciprocally with respect to the air gap portion 1b of the stator 1 and a plurality of magnets 7 coupled to an outer circumferential surface of the magnet holder 6 and forming induced magnetism with a coil 4. In the drawings, unexplained reference numeral 3b denotes a coil receiving slot.
However, the above-mentioned conventional reciprocating motor has the problem that it is difficult to manufacture the inner stator 2 and excessive expenses are required because the stator cores of the inner stator 2 have to be radially laminated.
Moreover, while the inner stator 2 is formed by radially laminating the stator cores sheet by sheet, the stator blocks 3a of the outer stator 3 have an arc shape whose inner and outer circumferential surfaces have the same length by laminating the stator cores sheet by sheet. Therefore, as shown in FIG. 4, the outer diameter curvature of the inner stator 2 and the inner diameter curvature of the outer stator 3 are different from each other, and this generates a gap (t) in the magnetic path connecting portion 1a between the outer circumferential surface of the inner stator 2 and the inner circumferential surface of the outer stator 3, thereby bringing about a degradation in motor performance caused by magnetic leakage.
In addition, the circumferential length of the stator blocks 3a is extended as both ends of the inner circumferential surface of the stator blocks 3a constituting the outer stator 3 are radially arranged so as to be in contact with each other. This may increase the use of the magnet 7, and therefore lead to an increase in manufacturing costs, when compared to the efficiency of the motor.